1. Field of the Invention
The present invention relates to a glass substrate processing method for forming a projection on a surface of a glass substrate or on a surface of a thin layer formed on a glass substrate, and to a glass component.
Priority is claimed on Japanese Patent Application No. 2005-336757, filed Nov. 22, 2005, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, as a method of processing a surface of a glass substrate using laser light, a method is known for forming an area having a high etching rate on a glass substrate by irradiating laser light onto the predetermined area of the glass substrate, and performing an etching on the glass substrate so that this area is removed, whereby forming a depression on the surface of the glass substrate.
Specifically, they irradiate pulse laser light having an energy density of 5 to 50 J/cm2 onto a transparent material for processing so as to include a surface of the material to be processed. Then, they perform an etching on the material for processing using a hydrofluoric acid solution having a relatively high concentration of 5.4 percent by weight, and remove the portions on which the laser light is irradiated so as to form holes (see, for example, JP2002-210730A). This publication discloses that the threshold value of the energy density for generating the structural changes necessary for the processing is 5 J/cm2 when the material to be processed is quartz glass.
Moreover, a method is also known for forming alteration areas having a high etching rate inside a quartz substrate by irradiating pulse laser light onto the quartz substrate, and then performing an etching on these alteration areas using an etchant having a temperature of 30° C. that is obtained by adding 14% of glycerol to a 10% hydrofluoric acid solution (see, for example, JP2004-359475A). In this publication, it is suggested that the concentration of hydrofluoric acid as well as the etching temperature required for forming depressions is still higher when glycerol is not added to the hydrofluoric acid solution.